Climent Bataller, Joan

La genética molecular es la rama de la genética que analiza, a nivel molecular, la estructura y la función del material genético basándose en métodos de biología molecular. A finales del siglo XX se empezaron a implementar técnicas con el fin de aislar, analizar y manipular a los ácidos nucleicos, así como a las proteínas codificadas por estos, dando lugar a la ciencia de la Biología Molecular. En 1973 Stanley Cohen (Standford University) y Herbert Boyer y cols. (University of California School of Medicine at San Francisco) insertaron un fragmento de ADN de un plásmido en otro, creando una molécula de ADN recombinante totalmente nueva, revolucionando así la biología. Anteriormente, la información acerca de la estructura y la organización de los genes se obtenía examinando sus efectos fenotípicos, pero el análisis genético molecular permite incluso leer las propias secuencias nucleotídicas, aportando nueva información sobre la estructura y la función de los genes. Las técnicas genéticas moleculares son múltiples y se emplean actualmente en muchos campos: además de en biología, se utiliza en ramas como la bioquímica, microbiología, biología del desarrollo, neurobiología, evolución, ecología y, por descontado, en diversas ramas de la veterinaria, donde es ahora indispensable para el diagnóstico de enfermedades o la selección de individuos en animales de compañía o ganadería, entre otros. Este manual tiene como objetivo proveer a los estudiantes del Grado en Veterinaria de la Universidad CEU Cardenal Herrera de las competencias necesarias para llevar a cabo algunas de las técnicas más empleadas durante el desarrollo de la investigación veterinaria y de la práctica clínica. Para ello, se incluye la descripción clara de los fundamentos teóricos de los principales métodos y la explicación, paso a paso, de las técnicas empleadas.

Since its emergence in March 2020, the SARS-CoV-2 global pandemic has produced more than 116 million cases and 2.5 million deaths worldwide. Despite the enormous efforts carried out by the scientific community, no effective treatments have been developed to date. We applied a novel computational pipeline aimed to accelerate the process of identifying drug repurposing candidates which allows us to compare three-dimensional protein structures. Its use in conjunction with two in silico validation strategies (molecular docking and transcriptomic analyses) allowed us to identify a set of potential drug repurposing candidates targeting three viral proteins (3CL viral protease, NSP15 endoribonuclease, and NSP12 RNA-dependent RNA polymerase), which included rutin, dexamethasone, and vemurafenib. This is the first time that a topological data analysis (TDA)-based strategy has been used to compare a massive number of protein structures with the final objective of performing drug repurposing to treat SARS-CoV-2 infection.

Polymorphisms in the PER3 gene have been associated with several human disease phenotypes, including sleep disorders and cancer. In particular, the long allele of a variable number of tandem repeat (VNTR) polymorphism has been previously linked to an increased risk of breast cancer. Here we carried out a combined germline and somatic genetic analysis of the role of the PER3VNRT polymorphism in breast cancer. The combined data from 8284 individuals showed a non-significant trend towards increased breast cancer risk in the 5-repeat allele homozygous carriers (OR = 1.17, 95% CI: 0.97–1.42). We observed allelic imbalance at the PER3 locus in matched blood and tumor DNA samples, showing a significant retention of the long variant (risk) allele in tumor samples, and a preferential loss of the short repetition allele (p = 0.0005). Gene co-expression analysis in healthy and tumoral breast tissue samples uncovered significant associations between PER3 expression levels with those from genes which belong to several cancerassociated pathways. Finally, relapse-free survival (RFS) analysis showed that low expression levels of PER3 were linked to a significant lower RSF in luminal A (p = 3 × 10−12) but not in the rest of breast cancer subtypes.

Background: Epidemiological and clinical evidence points to cancer as a comorbidity in people with autism spectrum disorders (ASD). A significant overlap of genes and biological processes between both diseases has also been reported. Methods: Here, for the first time, we compared the gene expression profiles of ASD frontal cortex tissues and 22 cancer types obtained by differential expression meta-analysis and report gene, pathway, and drug set-based overlaps between them. Results: Four cancer types (brain, thyroid, kidney, and pancreatic cancers) presented a significant overlap in gene expression deregulations in the same direction as ASD whereas two cancer types (lung and prostate cancers) showed differential expression profiles significantly deregulated in the opposite direction from ASD. Functional enrichment and LINCS L1000 based drug set enrichment analyses revealed the implication of several biological processes and pathways that were affected jointly in both diseases, including impairments of the immune system, and impairments in oxidative phosphorylation and ATP synthesis among others. Our data also suggest that brain and kidney cancer have patterns of transcriptomic dysregulation in the PI3K/AKT/MTOR axis that are similar to those found in ASD. Conclusions: Comparisons of ASD and cancer differential gene expression meta-analysis results suggest that brain, kidney, thyroid, and pancreatic cancers are candidates for direct comorbid associations with ASD. On the other hand, lung and prostate cancers are candidates for inverse comorbid associations with ASD. Joint perturbations in a set of specific biological processes underlie these associations which include several pathways previously implicated in both cancer and ASD encompassing immune system alterations, impairments of energy metabolism, cell cycle, and signaling through PI3K and G protein-coupled receptors among others. These findings could help to explain epidemiological observations pointing towards direct and inverse comorbid associations between ASD and specific cancer types and depict a complex scenario regarding the molecular patterns of association between ASD and cancer.

Alzheimer’s (AD) and Parkinson’s diseases (PD) are the two most prevalent neurodegenerative disorders in human populations. Epidemiological studies have shown that patients suffering from either condition present a reduced overall risk of cancer than controls (i.e., inverse comorbidity), suggesting that neurodegeneration provides a protective effect against cancer. Reduced risks of several site-specific tumors, including colorectal, lung, and prostate cancers, have also been observed in AD and PD. By contrast, an increased risk of melanoma has been described in PD patients (i.e., direct comorbidity). Therefore, a fundamental question to address is whether these associations are due to shared genetic and molecular factors or are explained by other phenomena, such as flaws in epidemiological studies, exposure to shared risk factors, or the effect of medications. To this end, we first evaluated the transcriptomes of AD and PD post-mortem brain tissues derived from the hippocampus and the substantia nigra and analyzed their similarities to those of a large panel of 22 site-specific cancers, which were obtained through differential gene expression meta-analyses of array-based studies available in public repositories. Genes and pathways that were deregulated in both disorders in each analyzed pair were examined. Second, we assessed potential genetic links between AD, PD, and the selected cancers by establishing interactome-based overlaps of genes previously linked to each disorder. Then, their genetic correlations were computed using cross-trait LD score regression and GWAS summary statistics data. Finally, the potential role of medications in the reported comorbidities was assessed by comparing disease-specific differential gene expression profiles to an extensive collection of differential gene expression signatures generated by exposing cell lines to drugs indicated for AD, PD, and cancer treatment (LINCS L1000). We identified significant inverse associations of transcriptomic deregulation between AD hippocampal tissues and breast, lung, liver, and prostate cancers, and between PD substantia nigra tissues and breast, lung, and prostate cancers. Moreover, significant direct (same direction) associations of deregulation were observed between AD and PD and brain and thyroid cancers, as well as between PD and kidney cancer. Several biological processes, including the immune system, oxidative phosphorylation, PI3K/AKT/mTOR signaling, and the cell cycle, were found to be deregulated in both cancer and neurodegenerative disorders. Significant genetic correlations were found between PD and melanoma and prostate cancers. Several drugs indicated for the treatment of neurodegenerative disorders and cancer, such as galantamine, selegiline, exemestane, and estradiol, were identified as potential modulators of the comorbidities observed between neurodegeneration and cancer.

Introduction: Learning molecular genetics techniques is part of the program of the genetics course of the veterinary degree. It is essential to maintain motivation and interest in genetics practice by using a common thread that connects with the students’ interests. This work describes the design, implementation, and results of a gamification strategy developed during two practical sessions in which the student becomes a geneticist to identify which dog a faecal sample collected from the street belongs to, as some municipalities currently do to promote hygiene and public health in their streets. The aim was for students to understand basic concepts and techniques in molecular genetics during these two sessions. This included learning how to extract DNA from different types of samples, describing the amplification using Random Amplification Polymorphic DNA (RAPD), and getting a better understanding of molecular markers and the theory behind Polymerase Chain Reaction (PCR). Methodology: In the first practice, students extracted DNA from fresh dog faeces, while also discussing various DNA sources and extraction methods. Then they used the extracted DNA to create a simulated database of fictional dogs associated with students. They quantified the DNA, analysed its quality, and prepared a dilution to 10ng/μL. In the second practice, the students used RAPD to identify individuals by matching DNA from a simulated collected faeces sample to their fictional dogs DNA database. They performed amplification reactions with various primers pairs, followed by gel electrophoresis, to compare DNA band patterns and identify the dog and the fictional student associated with the uncollected dog faeces. The advantages and limitations of the RAPD technique were discussed, along with its potential applications in veterinary science and genetics. Results and discussion: The students were successful in extracting DNA with concentrations over 100 ng/μL in most cases as well as a good purity with respect to proteins. However, it was found that there was usually a low quality of DNA with respect to salts, although this did not influence the results of the second practice. They were able to generate reproducible RAPD profiles with all primer pairs. The unknown individual could be easily recognized within the database. Conclusions: It is concluded that this educational proposal is an effective option for teaching DNA extraction and the RAPD technique, as well as for many molecular genetics terms and concepts and contributes to the comprehensive training of future veterinary professionals. Additionally, the educational and social value of the practices are highlighted, as they promote interest in science, respect for the environment, and civic responsibility.